In certain industrial polishing and cleaning operations, it has been common practice to use a rotary brush whose filaments are impregnated with a polishing fluid, the fluid usually consisting of a liquid carrying fine particles of abrasive. The brushes usually used to have bristles made of a natural fiber. The most common fiber used is tampico which has sufficient porosity to carry the polishing compound, while at the same time, when suitably treated, having sufficient stiffness to drive the abrasive against the article to be polished with sufficient force. The supply of such natural fiber, however, is not only limited, but seems to be decreasing. For that reason, manufacturers of industrial brushes have sought a substitute material for the bristles.
One porous form of industrial brush filament is produced by twisting a fine wire. Such a brush is shown in the U.S. patent to Batemen U.S. Pat. No. 3,583,020. Such filaments of twisted wire (and even similar filaments made by twisting wire together in groups) have sufficient stiffness but they lack any ability to hold the grinding compound. It has also been suggested, for instance, in the patent of Overbeke U.S. Pat. No. 2,401,956 that the filaments be in the form of a cord braided from a natural fiber such as cotton. In order to prevent the filaments from being limp, the braid may be impregnated with a glue which hardens and provides some stiffness. It has been found, however, that such filaments wear quite readily and, furthermore, the impregnation of the pores in the braided cord leaves no porosity for the absorption of polishing compound. Furthermore, there is a tendency for the glue to break down in a short time and to leave the filaments too limp to provide the necessary polishing forces. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide an industrial brush adapted in polishing and cleaning operations to take the place of brushes whose filaments are formed of natural fibers, such as tampico.
Another object of this invention is the provision of an industrial brush of the rotary type having filaments formed of readily-obtainable artificial materials.
A further object of the present invention is the provision for use with a polishing slurry (or other media) of an industrial brush whose filament are formed of synthetic fibers.
It is another object of the instant invention to provide an industrial rotary brush having filaments formed of synthetic resin and having a high degree of stiffness, but which is capable of absorbing and holding polishing and cleaning compounds in the interstices formed by a braided configuration.
A still further object of the invention is the provision of an industrial rotary brush having a filament with an artificial resin core in which abrasive particles are embedded and an outer layer of a tough porous material formed from an artificial resin.
It is a further object of the invention to provide an industrial brush having a filament with a solid inner core of sacrificial material containing abrasive particles and a porous outer layer of a tough wear-resistant material.
Another object of the invention is the provision of an industrial brush in which the physical action of the filaments can be regulated and controlled by virtue of the braided construction; in which braided monofilaments are used to reduce the areas of stress concentration, thus eliminating a primary cause of long filament breakage; in which braided monofilaments are used to preclude compacting of the face of the brush into a narrow face (knifing) at the periphery; in which strands of braided filaments act as a family of filaments, thus providing a density at periphery so distributed as to provide equal filament contact with all surfaces and all protuberances on such surfaces that are being brushed; in which braided strand configuration is provided, so that filament deflection can be controlled; in which large amounts of filaments give stiffness, but because of the braided tuft configuration, the brush gives many more cutting points; in which large monofilaments give stiffness, but, because of the braided strand configuration, individual monofilaments are not subjected to excessive concentration of stresses and consequently fatigue life is improved; in which the braids of the monofilament are related to each other in such manner as to permit them to mutually support each other, so that the increased number of monofilaments attainable at periphery permits longer life of the brush; in which braided tuft construction provides an action that is intermediate to the harsh impact action of the conventional knot or tufted brush, and the more uniform softness of conventional crimped wire brushes, while at the same time having a marked reduction in breakage; in which is obtained a unique value for brushing resilient materials so that unusually long life can be attained when brushing such materials as rubber, leather, plastic, etc., which normally cause reduced fatigue life; in which is obtained a braided tuft rotary brush of small diameter that is denser than is possible in brushes of other tuft construction, even where their tufts are placed as closely together as possible at the hub which leaves insufficient density at the periphery; in which braided tuft configuration permits simple and relatively inexpensive assembly techniques to be used; in which braided strands permit their being secured firmly against longitudinal movement; in which braided strands of monofilament are crimped to provide a damping effect by interengagement of the tufts of filament with each other at fixed intervals along their length; in which braided tufts of relatively fine monofilaments are placed in relationship with each other in such a manner that a well-balanced construction is permitted that would be strong enough to resist bursting forces which might be encountered in use; in which a high safety factor is obtained due to the well-balanced construction possibilities inherent in this braided type construction; and in which a design is obtainable that permits it to be used singly or in multiples, narrow or wide face, in any diameter that brushes might be required.
Another object of the invention is the provision of a brush which lends itself to further treatment, impregnation, or encapsulation.